Backfire

[Greeny_SA]

Probably more importantly if the pair wasn't blocked off whilst taking A/F readings and building your fuel map then your maps not worth a cracker as the Pair injects air into the exhaust giving lean (false) mixture readings. She will be running fatter than a pregnant dog BIATCH on heat
Personally I'd go back and ask for the map to be redone >>>>>>>>> nicely of course.

Avante previous tune would have been with a Yosh Box set up

Bloody good point Pete, that's why I'm a Beer Plumber.